// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using Microsoft.EntityFrameworkCore.Query.SqlExpressions;

namespace EntityFrameworkCore.Jet.Query.ExpressionTranslators.Internal;

/// <summary>
///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
///     the same compatibility standards as public APIs. It may be changed or removed without notice in
///     any release. You should only use it directly in your code with extreme caution and knowing that
///     doing so can result in application failures when updating to a new Entity Framework Core release.
/// </summary>
/// <remarks>
///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
///     the same compatibility standards as public APIs. It may be changed or removed without notice in
///     any release. You should only use it directly in your code with extreme caution and knowing that
///     doing so can result in application failures when updating to a new Entity Framework Core release.
/// </remarks>
public class JetDateOnlyMemberTranslator(ISqlExpressionFactory sqlExpressionFactory) : IMemberTranslator
{
    private static readonly Dictionary<string, string> DatePartMapping
        = new()
        {
            { nameof(DateTime.Year), "yyyy" },
            { nameof(DateTime.Month), "m" },
            { nameof(DateTime.DayOfYear), "y" },
            { nameof(DateTime.Day), "d" }
        };

    private readonly ISqlExpressionFactory _sqlExpressionFactory = sqlExpressionFactory;

    /// <summary>
    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
    ///     any release. You should only use it directly in your code with extreme caution and knowing that
    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
    /// </summary>
    public virtual SqlExpression? Translate(
        SqlExpression? instance,
        MemberInfo member,
        Type returnType,
        IDiagnosticsLogger<DbLoggerCategory.Query> logger)
        => member.DeclaringType == typeof(DateOnly) && DatePartMapping.TryGetValue(member.Name, out var datePart)
            ? _sqlExpressionFactory.Function(
                "DATEPART",
                [_sqlExpressionFactory.Constant(datePart), instance!],
                nullable: true,
                argumentsPropagateNullability: [false, true],
                returnType)
            : null;
}
